With the huge depletion of limited fossil fuels and increasing environmental issues, the utilization of renewable energy such as biomass has become a promising approach for mitigating adverse environmental impacts and realizing sustainable development. Bio-oil derived from lignocellulosic biomass is a potential alternative feedstock for fuels due to its abundant reserve and high energy density. The oxygen removal by catalytic hydrodeoxygenation (HDO) is considered to be one of the most effective technologies to upgrade bio-oil. So, it is crucial to find an appropriate catalyst for the HDO process of lignin-derived phenolic compounds. Generally, mono-metal copper is regarded as a less active catalyst for the saturated hydrogenation of aromatic rings - contained compounds. This viewpoint could be corrected by one of our recent findings. In this study, a series of copper phyllosilicate nanotube catalysts with different Cu/Si ratios was prepared and applied in the HDO of lignin derived compounds. Most notably, using the non-precious metal Cu acted as the only active component, we got an unforeseen result. The yield of cyclohexane can be up to 97.8% for Cu1Si1 at 230 °C. For the simplified procedure of phenol HDO, the hydrogenation of phenol is much faster than the conversion of cyclohexanol (71.2 versus 23.3 mmol/(gcat h)), and the apparent activation energies of these two steps was calculated to be 67.9 and 103.8 kJ/mol, respectively. It could be deduced that the conversion of cyclohexanol is the controlling step in the cascade reaction process. Moreover, it was also deduced that Cu0 promotes hydrogenation activation and Cu+ is responsible for the adsorption and further conversion of cyclohexanol. The synergy of Cu+ and Cu0 species promotes the whole reaction process. These results open a gate for the application of non-precious metal catalyst in the HDO of lignin derived phenols.

Copper phyllosilicate nanotube catalysts for hydrodeoxygenation of lignin-derived phenols

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.